Wedge type safety brake



Sept. 13, 1955 G. D. HIGGINS WEDGE TYPE SAFETY BRAKE 2 Sheets-Sheet 1 Filed Feb. 26, 1954 V. B a 6 2 z 1 Z 1 Z .1 7 7 3 w M 4 3 I z Wu 4 4 EVE r E mwi 2 V is M v fl/ 1 W Sept. 13, 1955 e. D. HIGGlNS 2,717,663

WEDGE TYPE SAFETY BRAKE 2 Sheets-Sheet 2 Filed Feb. 26, 1954 ATramvz-IY United States Patent 01 WEDGE TYPE SAFETY BRAKE George D. Higgins, Wharton, N. 1., assignor of onefourth to Martin J. Brophy, Wharton, N. J.

pp on Februar 26, 1954, Serial No. 412,861 1 Claim. (Cl. 133-44 This invention relates to safety devices for cable suspended elevators, mine cages or ore skips and more particularly to a safety brake that will prevent the elevator, mine cage or ore skip from descending to the bottom of the shaft should a break occur in the suspension cable.

It is a well known fact that if the suspension cable of an elevator or the like were to break that the elevator would immediately drop to the bottom of the elevator shaft unless some safety device had been provided to stop its descent.

An object of the invention, therefore, is to provide a wedge type safety brake that will immediately operate, upon the breaking of the suspension cable of an elevator.

In mines, the cages for the miners and the ore skips are all operated by a suspension cable and should the cable be accidently cut or break, due to wear, the cage or skip would immediately drop to the bottom of the shaft. Serious damage, as well as the death of the occupants of the cages, often occurs and it is the usual procedure to require safety devices to prevent such accidents.

Elevators in otfice buildings, hotels and apartment houses have elevators of the cable suspension type and the present safety device has been provided and is so constructed that it can be associated with either of the types of elevators or cages previously described.

Another object of the invention is to provide a wedge type safety brake that has to be released by the raising of the cage or elevator for the more the cage or elevator has a tendency to descend the more firmly will the brake retain the cage or elevator in fixed relation to the shaft.

With the above and other objects and advantages in view A the invention consists of the novel details of construction, arrangement and combination of parts more fully hereinafter described, claimed and illustrated in the accompanying drawings in which:

Fig. 1 is a front elevational view of an embodiment of the invention in position on the guide rail (partly broken away) of a cable suspended elevator or the like;

Fig. 2 is a side elevational view of the embodiment of the invention;

Fig. 3 is a transverse sectional view on the line 3-3 of Fig. 1 looking in the direction of the arrows;

Fig. 4 is a transverse sectional view on the line 44 of Fig. 1 looking in the direction of the arrows;

Fig. 5 is a fragmentary sectional view on the line 5-5 of Fig. 3 showing the brake shoes in released position;

Fig. 6 is a front elevational view of the embodiment of the invention in position on the guide rail, partly broken away, of a cable suspended elevator showing the cable broken and the brake shoes in set position;

Fig. 7 is a transverse sectional view on the line 77 of Fig. 6 looking in the direction of the arrows; and

Fig. 8 is a fragmentary sectional view on the line 8-8 of Fig. 7 looking in the direction of the arrows showing the brake shoes in set position.

Referring more in detail to the drawings, wherein like parts are indicated by like reference numerals, the ref- 2,7115% Patented Sept. 13, 1955 erence numeral 10 indicates the guide rail of a cable suspended elevator with which the embodiment of the invention is associated.

The elevator is usually provided with a frame which is of channel formation and which is shaped to slidably engage the guide rail 10, there being a guide rail and frame at the opposite sides of the elevator. The guide rail usually is mounted in fixed relation to the shaft and the frames move on the guide rails as the elevator rises and descends in the elevator. For the purpose of illustrating the embodiment of the invention, a small portion of the frames engaging the guide rails is shown and is designated by the reference numeral 11, and, except for the manner in which it is associated with the embodiment of the invention, forms no part thereof.

it is also to be understood that an embodiment of the invention is to be associated with each guide rail used with the elevator.

A suspension cable 12 for the elevator is attached to one of the ends of the diverging cables 13 and 14, respectively, by means of an eye 15 formed on a king bolt 16 while the opposite ends of the cables 13 and 14 are fixed to eyes 17 mounted on the frame 11 of the elevator.

The king bolt is vertically positioned in parallel relation to the guide rail 10 and an upper guide plate 18 and a lower guide plate 19 are fixed to the frame 11 in spaced relation to each other and slidably receive the king bolt 16. A tubular guide sleeve 20 extends between the guide plates 18 and 19 and are fixed thereto to also slidably receive the king bolt 16.

With the suspension cable 12 connected to the king bolt 16, the eye of the king bolt 16 supports the full weight of the elevator or cage.

The lower end of the king bolt 16 is threaded to receive lock nuts 21. A yoke 22 is mounted on the lower end of the king bolt 16 with one portion of the yoke 22 in engagement with the lock nuts 21.

A spring 23 is interposed between the lower guide plate 19 and the other portion of the yoke 22 and when the suspension cable 12 and king bolt 16 are under tension the spring 23 is contracted.

Horizontally disposed diametrically extending, oppositely opposed L-shaped arms 24 and 25, respectively, are engaged at the inner ends of the base portions 26 by the yoke 22 and as long as tension is on the cable 12 and king bolt 16, these arms will remain in the position as shown in Fig. 1.

Stem portions 27 of the arms 24 and 25 extend at right angles to the base portions 26 and are pivotally mounted in the frame 11 on opposite sides of the rail 10.

Fixed to each of the stem portions 27 of the arms 24 and 25 and movable therewith is a disc 28 which is apertured to eccentrically receive the hooked end of a connecting rod 29. Arcuate projections 30 are provided on the frame 11 to protect the discs 28 so that they will move freely as will be later described. An extension 31 is secured to the outer end of each stem portion 27 of the arms 24 and 25 and such extension extends outwardly of the arcuate projections 30.

Safety springs 32 are connected at one end to the extensions 31 and at 33 the opposite end of the springs 32 are connected to the frame 11, for a purpose to be later described.

The opposite hooked ends of the rods 29 are connected at 34 to movable wedge shaped brake shoes 35 which are adapted to coact with stationary brake shoes 36 which are fixed to the frame 11 on opposite sides of the rail 10.

In the operation of the device with tension on the cable 12 and king bolt 16, the device will assume the normal position of Fig. l and the elevator will be functioning normally.

Should, however, the cable 12 break, as in Fig. 6, the device will operate as follows:

The spring 23 will expand, pushing the king bolt downwardly. The yoke 22 will pivot the arms 24 and 25 downwardly. This action will cause the rotation of the discs, tending to pull upwardly on the movable brake shoes 35. A wedging action between the movable brake shoes 35 and the stationary brake shoes 36 will jam the frame 11 and prevent the elevator or cage from descending. To further add to the expansion urge of the spring 23 the springs 32 will contract to add extra force in moving the arms 24 and 25 into the position of Fig. 6.

It will be apparent that the weight of the elevator and cage will be assumed by the coaction of the brake shoes 35 and 36 one with the other and the elevator and cage will not move downwardly. To release the brake shoes the suspension cable 12 will have to be repaired or re placed. Once this is accomplished and the elevator or cage is moved upwardly, tension will again be placed on the king bolt 16 causing the arms 24 and 25 to move upwardly and assume their normal or released position, as in Fig. 1.

There has thus been provided a safety device for cable suspended elevators and it is believed that the operation and construction of the embodiment of the invention will be apparent to those skilled in the art.

It is also to be understood that various changes may be made in the minor details of construction, arrangement and combination of parts without departing from the spirit of the invention or the scope of the appended claim.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

The combination of a frame for a cable-suspended elevator, a guide rail for slidably mounting said frame, a fixed brake shoe mounted on said frame on each side of said rail, a movable brake shoe positioned between each fixed shoe and said rail, a cable supporting said frame, and means carried by said frame for moving said movable shoes into engagement with said rail and fixed shoes upon breaking of said cable, said fixed shoes having inwardly and upwardly tapering inner faces, and said movable shoes being wedge-shaped and normally out of wedging engagement with said fixed shoes and said rail.

References Cited in the file of this patent UNITED STATES PATENTS 328,098 Wilcox Oct. 13, 1885 604,557 Baum May 24, 1898 2,538,477 Smith Jan. 16, 1951 2,623,614 Herr Dec. 30, 1952 

